1. Field of the Invention
The present invention relates to truss rod assemblies for adjusting the curvature of the neck of a musical instrument and, more particularly, to an improved truss rod assembly wherein the truss rod is flattened to increase the flexibility thereof.
2. Description of the Prior Art
In musical instruments of the type including a body and a neck, such as a guitar and an electric bass, where the instrument neck is made from wood, the neck is subject to warpage from all of the factors which usually cause such phenomenon. Since it is highly important, in such an instrument, for the fret board thereof to remain perfectly planar, it has become a common practice to provide such an instrument with means for adjusting the curvature of the neck to compensate for such warpage.
One of the more common types of such means includes a truss rod assembly positionable in the neck of the musical instrument. A common truss rod assembly is positionable within a slot in the side of the neck opposite from the fret board and includes an elongate truss rod, a fixed anchor nut at one end of the truss rod, and a fixed washer and tension nut at the other end of the truss rod. In operation, rotation of the tension nut moves the other end of the truss rod relative to the washer and tension nut, increasing or decreasing the tension on the truss rod and simultaneously adjusting the curvature of the instrument neck.
The truss rod is an elongate, cylindrical member having a linear axis before being inserted into the slot in the instrument neck, but the slot is curved so that the opposite ends of the truss rod are positioned adjacent the fret board and the center of the truss rod is positioned adjacent the opposite side of the instrument neck. The truss rod assembly is inserted into the slot in the instrument neck and the slot is filled with an elongate fill strip which is made from wood and has the configuration of the slot in the instrument neck after the truss rod assembly is inserted thereinto. The sides of the slot and the fill strip are coated with glue and the fill strip is pressed into the slot.
A number of problems have been encountered in use of truss rod assemblies of the above type. First of all, because of the curvature of the slot in the instrument neck and the thickness of the truss rod, the central portion of the fill strip is normally very thin which creates the possibility of it cracking in handling and failure in use of the instrument. More importantly, a cylindrical truss rod is not very flexible, making the above assembly procedure difficult to accomplish. Because of the inflexibility of the cylindrical truss rod, it has often been necessary to hold the fill strip with a substantial pressure during the setting of the glue holding same. Even with such pressure, the truss rod often ends up being spaced from the base of the slot in the instrument neck and simply does not operate properly once the neck has been assembled.